While I was in Bristol a few months ago, I went to Bath. It is the site of a remaining Roman bathhouse. And after you visit the bathhouse, you can go take a bath in the disgusting mineral water (yes, I drank the gross stuff). The town itself was quite charming, but very touristy and very, very tiny.
I only spent about 6 hours in the town so I didn't get to do much, but I saw a lot. After paying an arm and a leg to visit the Roman Baths, I got to go on a FREE tour of the city. I know, you're thinking 'a free tour, it couldn't have been that good,' but it was. A little retired man took us all around the city and told us a ton about the architecture and the history of most of the major buildings.
Maybe the most fascinating thing for me was looking at and hearing the history of Jane Austen's house. I actually learned quite a lot about her from the tour guide and it was really cool seeing where she lived, walked, etc. I also really appreciated all the Georgian houses and the columns. They're really lovely.
I'm not sure I would recommend a trip to Bath. If you are in the area, it's a great little half-day visit, but I don't think I would make a special trip just to see it. After all, you can go to Rome to see Roman baths and there are several other interesting small towns in England.